In this study, we investigated the effects of oxidized cholesterol and oxidized sitosterol in mice. The major novel finding in this study is that the i.p. application of plant sterols or their oxidation products result in elevated plasma levels and increases sterol concentrations in the arterial wall. Interestingly, application of non-oxidized cholesterol or sitosterol increases their respective plasma concentrations but does not give rise to increased oxysterol or oxyphytosterol concentrations suggesting that endogenous oxidation does not play a major role in this context. Finally, only the elevation of 7β-OH-sitosterol resulted in increased ROS production in the arterial wall, but this did not affect endothelial cell quantification, endothelial cell migration, endothelial function, and early atherosclerotic lesion development.